Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

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Query: EC:3.2.1.17 (lysozyme)
21,489 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Following fixation with formalin or glutaraldehyde, the protein content of bovine serum albumin, lysozyme, non-disintegrated yeast cells and liver nuclei of mice is determined by means of a brom-phenol blue staining procedure and the widely used Lowry-technique. The bromphenol blue technique permits determinations of soluble as well as particulate proteins or protein mixtures fixed with up to 6% formalin or 2% glutaraldehyde. Recovery rates differ no more than 20% as related to unfixed controls. Using the bromphenol blue method it is not necessary to separate aldehyde or any interfering material by additional steps prior to determination. Factors for correcting protein content of biological material after aldehyde treatment are available. In this way, comparative biochemical as well as cyto- and histochemical investigations of enzymatic activities after aldehyde fixation are possible. Some advantages of the bromphenol blue technique with special reference to the analysis of particulate and/or aldehyde-fixed specimens are discussed.
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PMID:[Essay of proteins after aldehyde treatment in biological objects (author's transl)]. 8 Sep 8

As revealed, the action of lysozyme on the cells of Clostridium perfringens BP-6K led to the formation of not only typical spheroplasts, but also of cells whose peripheral parts of the cytoplasm were fragmented by membrane component. Small bodies framed by the membrane proper and containing granular and fibrillar components were formed. They were polymorphic in osmium treatment, and had smooth contours in preliminary use of aldehyde fixation. In the latter case a dense lumpy material analogous to the one which fills the periplasmic zone and serves as a rigid wall component formed at the surface of the protoplasm and bodies-fragments. In case of escape of the bodies into the external environment through the perforations in the cell wall the principal mass of the protoplast remains intact. The morphology of the bodies-fragments indicated a principal possibility of their autonomic existence. It is supposed that the phenomenon described could serve as one of the mechanisms of L-cell formation.
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PMID:[Protoplast fragmentation as one of the possible mechanisms of L-transformation of bacteria (Clostridium perfringens)]. 20 29

The amino groups of hen egg white lysozyme were reductively alkylated by the reaction with aliphatic aldehydes of various chain lengths and with two aldehydes of different steric hindrance at pH 7.5 and 4 degrees for 3 h. About four of the original six lysine residues were modified by the reaction with acetaldehyde, n-butylaldehyde or n-hexylaldehyde. About three lysine residues were 2,2-dimethylpropylated with trimethylacetaldehyde while a single residue was modified with benzaldehyde. The thermal stabilities of these alkylated lysozymes were investigated by differential scanning calorimetry (DSC) at different acidic pH values. Alkylation thermally destabilized the proteins, depending not only on the extent of modification but also on the size of the substituent. The alkylated derivatives were 8-19 kJ/mol less stable than native lysozyme at 25 degrees and pH 3.0. The temperature dependences of the activities of the alkylated lysozymes against ethylene glycol chitin indicated that the orders of the optimum temperatures and the maximum activities were exactly the same as the order of the thermal stabilities.
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PMID:Effect of alkylation with different sized substituents on thermal stability of lysozyme. 144 66

Lysozyme was immobilized by two different methods in two different ways in order to obtain a preparation with an activity as high as possible toward a macromolecular substrate. The enzyme was bound as a Schiff base to a silicate carrier by using oxidized dextrans of different lengths as spacer and also was bound to controlled pore aminoglass via pyridino-4-aldehyde and BrCN. The latter preparations had activities up to 2.5% of the free lysozyme.
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PMID:Degradation of bacterial cell walls by immobilized lysozyme. 246 90

The generation and characterization of ubiquitin (Ub)-aldehyde, a potent inhibitor of Ub-C-terminal hydrolase, has previously been reported. We now examine the action of this compound on the Ub-mediated proteolytic pathway using the system derived from rabbit reticulocytes. Addition of Ub-aldehyde was found to strongly inhibit breakdown of added 125I-labeled lysozyme, but inhibition was overcome by increasing concentrations of Ub. The following evidence shows the effect of Ub-aldehyde on protein breakdown to be indirectly caused by its interference with the recycling of Ub, leading to exhaustion of the supply of free Ub: Ub-aldehyde markedly increased the accumulation of Ub-protein conjugates coincident with a much decreased rate of conjugate breakdown. release of Ub from isolated Ub-protein conjugates in the absence of ATP (and therefore not coupled to protein degradation) is markedly inhibited by Ub-aldehyde. On the other hand, the ATP-dependent degradation of the protein moiety of Ub conjugates, which is an integral part of the proteolytic process, is not inhibited by this agent. Direct measurement of levels of free Ub showed a rapid disappearance caused by the inhibitor. The Ub is found to be distributed in derivatives of a wide range of molecular weight classes. It thus seems that Ub-aldehyde, previously demonstrated to inhibit the hydrolysis of Ub conjugates of small molecules, also inhibits the activity of a series of enzymes that regenerate free Ub from adducts with proteins and intermediates in protein breakdown.
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PMID:Ubiquitin-aldehyde: a general inhibitor of ubiquitin-recycling processes. 303 53

Although a number of skin diseases are characterized by the presence of an increased number of phagocytes in their lesions, the effects of alcohol on phagocytic functions are not clearly understood. Therefore, we measured the influence of ethanol and acetaldehyde on the generation of oxygen radicals, chemotaxis and the release of lysosomal enzymes from human phagocytes. We added 0.03%-3% ethanol and 0.005%-0.25% acetaldehyde to cell cultures. We found that both ethanol and acetaldehyde suppressed the generation of oxygen radicals from granulocytes and monocytes; the ID50 was achieved at concentrations of approximately 0.25% for ethanol and 0.03% for acetaldehyde. A significant inhibition of granulocyte chemotaxis was first noted with 0.063% ethanol and 0.016% acetaldehyde. Ethanol and acetaldehyde inhibited the release of the lysozyme of monocytes at concentrations of greater than 0.75% and greater than 0.03% respectively, but granulocytes were unaffected; the release of beta-glucuronidase and lactate dehydrogenase remained stable. Due to the high volatility of the agents, especially acetaldehyde, under the experimental procedures employed, the actual concentrations of the agents were probably lower and similar to those measured in vivo. Our results indicate that defined phagocytic functions are strongly inhibited by concentrations of ethanol and acetaldehyde which are associated with moderate to severe inebriation.
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PMID:Effects of ethanol and acetaldehyde on phagocytic functions. 398 69

Rat mast cells fixed in Carnoy's fluid were stained with iron alum-Alcian Blue--Safranin solution after pre-treatment with strong electrolyte solutions including acids, neutral salts and alkalis. Although both red and blue mast cells were observed without pre-treatment, most mast cells were stained blue and a few red when they were stained after the pre-treatment. Mast cell granules contain salt complexes formed between basic proteins and acidic polysaccharides through ionic linkages between protein basic groups and polysaccharide sulphate and carboxylic acid groups. It is suggested that when sections are treated with strong electrolyte solutions, complexes are broken by disruption of ionic linkages and sulphate and carboxylic acid groups of polysaccharides masked by basic proteins become available for binding Alcian Blue. This was confirmed by model experiments performed with smears of a heparin-lysozyme complex. When mast cells were fixed in aldehyde-containing fixatives, no effects of strong electrolyte solutions on the staining properties of mast cell granules were revealed.
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PMID:Effects of strong electrolytes on the iron alum--Alcian Blue--Safranin staining of mast cell granules of the rat. 616 Jan 27

Incubation of lysozyme with acetaldehyde (0.44 M) at room temperature for 2 h produces a 62% inhibition of enzymic activity. Because the active site cleft contains tryptophyls, asparagine, glutamine, and an arginine residue, and because acetaldehyde reacts with indoles, amides, and guanidines, it is suggested that these sites are likely ones for alkylation. The epsilon-amino groups of lysines on the surface of the molecule are also susceptible to covalent modification. Total acetylation of lysozyme has been reported to inactivate the enzyme. These results suggest the possibility that inactivation of a fraction of the lysozyme activity by acetaldehyde may decrease the effectiveness of the enzyme in chronic alcoholics, thereby leading to an increased potential for susceptibility to bacterial infection.
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PMID:Acetaldehyde-modified lysozyme function: its potential implication in the promotion of infection in alcoholics. 777 70

Myeloperoxidase of neutrophilic leukocytes (MPO) at pH 4.0 to 6.5 mediated oxidation of Cl- ions, yielding hypochloride (OCl-) which then reacted with amino acids and polypeptides. Thiol and thioether groups may be oxidized to disulfide or to sulphoxides and sulphonic acids respectively. Tryptophanyl residues yielded 2-oxoindole. Epsilon amino groups of lysine produced chloramine which, however, decomposed, yielding aldehyde residues. Bovine serum albumin treated with MPO-Cl-H2O2 system yielded derivatives with a decreased affinity to antialbumin antibodies and increased electrophoretic mobility. Albumin aldehyde derivatives were also obtained. At H2O2 molar ratio with albumin 20:1, a precipitation of albumin occurred, due to the formation of new polymeric albumin derivatives. The lysozyme (LZM) lost its enzyme activity when 1.4 to 1.8 mol of H2O2 per 1 mol of LZM was used. Addition of H2O2 above molar ratio 5:1 produced LZM polymerization to di-, tri-, tetra and pentameric derivatives. IgA exposed to the MPO-Cl-H2O2-Cl- system split into light chains (molecular weight: 25.8 kDa), heavy chains (molecular weight: 81.8 kDa) and a third polypeptide which size was half the light chain size (molecular weight: 13.9 kDa). The IgA exceeding the HOCl ratio 1:350 (mg/mumol) produced both precipitation and degradation of the IgA polypeptide structure. The treatment of IgG with HOCl released a fragment corresponding to half the light chain size, the light chain, and the heavy chain, whereas HOCl treatment of IgM released only a fragment which size was smaller than the heavy chain and another fragment which size was the same as the light chain. The MPO-Cl-H2O2 system produced many specific changes in protein structures.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Oxidative modification of protein structures under the action of myeloperoxidase and the hydrogen peroxide and chloride system. 785 48

6-O-[(2-Hydroxyethyl)poly(2-oxyethyl)]chitosan ("glycolchitosan") was oxidatively cleaved with nitrous acid and then partly acetylated with acetic anhydride, reacted with bromoacetyl-N-hydroxysuccinimide, and reacted further with acetic anhydride. Conditions were selected, including fractionation by size-exclusion chromatography, so that the resulting "Chitin Leash" had an estimated, average molecular weight of 10,000 (dextran standards), corresponding to a length of approximately 40 sugar residues. It possessed 0.9 terminal aldehyde and 2.6 random (presumably) side-chain bromoacetyl reactive groups per chain (average values). As a model system, the Chitin Leash was used to crosslink staphylococcal nuclease (SNase) to ribonuclease A (RNase) with retention of 75 and 78%, respectively, of the starting enzyme activities. For this coupling, the Nase was first converted to a sulfhydryl SNase derivative which retained 74% of the activity of starting enzyme. The yields in this synthesis were: 13% Chitin Leash from glycolchitosan, 24% Chitin Leash-RNase from Chitin Leash and 45% SNase-Chitin Leash-RNase from the latter conjugate. The ratio of SNase to RNase in this conjugate was 1.0:0.94. In a second preparation, in which [14C]acetic anhydride was used, a longer reaction time was employed for the coupling of Chitin Leash to RNase. This gave a 1.0:1.8:0.95 molar ratio of Nase: [14C]Chitin Leash: RNase, revealing multiple attachment of the [14C]Chitin Leash to RNase. The activity of the RNase in the final conjugate was 20%. The latter conjugate was approximately 70% hydrolyzed by diaminooctyl-succinyl-lysozyme, disconnecting the two enzymes while not affecting their activities.
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PMID:"Chitin Leash": a polysaccharide heterobifunctional cross-linking agent which can be cleaved by lysozyme. 837 39


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